1. Field of the Invention
The present invention relates to a radiation image pickup apparatus and a radiation image pickup system, which detect radiation. Particularly, the present invention relates to a radiation image pickup apparatus and a radiation image pickup system used for a medical image diagnosis apparatus, an analyzer, and so on.
2. Description of the Related Art
Recently, a radiation image pickup apparatus having a large area, which is about 40 cm×40 cm, has been developed. US2003/0173493 and US2007/0075247 disclose a structure in which one image sensing surface is formed by arranging, side by side, a plurality of image pickup substrates including photoelectric-conversion elements in order to implement the radiation image pickup apparatus with such a large area. Also, these literatures disclose a structure in which a polyimide film is formed on the plurality of image pickup substrates and between the plurality of image pickup substrates, and a scintillator of alkali halide-based columnar crystal is formed on the polyimide film by vapor deposition.
According to the radiation image pickup apparatus disclosed in US2003/0173493 and US2007/0075247, the plurality of image pickup substrates is fixed onto a base via a connecting member, and the polyimide film is disposed as a planarization layer on the plurality of image pickup substrates and between the plurality of image pickup substrates. With this structure, in the case where moisture enters from between the image pickup substrate and the base through the connecting member, the moisture may enter between the image pickup substrates as well. Since the polyimide film is not capable enough to reduce such moisture entrance, deliquescence of the scintillator or characteristic deterioration thereof may occur due to the moisture.